[Qemu-discuss] Qemu-nbd not working

[Igor Liferenko]

Hello,

I start virtual machine this way:

$ qemu-img create -f qcow2 newcd-qemu.qcow2 10G
$ qemu-system-i386 -enable-kvm -display vnc=localhost:0 -hda
newcd-qemu.qcow2 -cdrom newcd-qemu.iso -m 256 -boot once=d

While virtual machine operation I have these logs in dmesg:

[Mon Oct 26 23:35:18 2015] kvm: zapping shadow pages for mmio
generation wraparound
[Mon Oct 26 23:35:18 2015] kvm: zapping shadow pages for mmio
generation wraparound
[Mon Oct 26 23:35:21 2015] kvm [15181]: vcpu0 disabled perfctr wrmsr:
0xc2 data 0xffff
[Mon Oct 26 23:35:21 2015] kvm [15181]: vcpu0 unhandled rdmsr: 0x570
[Tue Oct 27 00:05:27 2015] kvm [15181]: vcpu0 disabled perfctr wrmsr:
0xc2 data 0xffff
[Tue Oct 27 00:05:27 2015] kvm [15181]: vcpu0 unhandled rdmsr: 0x570

And after on the commands

$ sudo modprobe nbd max_part=16
$ sudo qemu-nbd -c /dev/nbd0 newcd-qemu.qcow2
$ sudo mount /dev/nbd0p1 /mnt/
mount: special device /dev/nbd0p1 does not exist
$ sudo umount /mnt/
umount: /mnt/: not mounted
$ sudo qemu-nbd -d /dev/nbd0

I have these logs in dmesg:

[Tue Oct 27 01:17:39 2015] nbd: registered device at major 43
[Tue Oct 27 01:17:40 2015]  nbd0: p1 p2 < p5 >
[Tue Oct 27 01:17:42 2015] block nbd0: NBD_DISCONNECT
[Tue Oct 27 01:17:42 2015] block nbd0: Receive control failed (result -32)
[Tue Oct 27 01:17:42 2015] block nbd0: queue cleared

Qemu version: 1:2.4+dfsg-4 (debian testing weekly build from 19.10.2015)

Note: on another computer the same commands run without errors.

Ready to supplement any required tests and logs.

Regards,
Игорь